Up to 60 Conservatives MPs could be deselected as revenge for ousting Boris Johnson, one of his supporters has said.
David Campbell Bannerman said “quite rightly” party members would block those not seen as loyal to the disgraced ex-PM.
The former MEP is chairman of the Conservative Democratic Organisation, which wants to "restore democracy" within the party.
The organisation, led by hardline Brexiteers and Johnson loyalists, is angry Rishi Sunak was handed the keys to No10 without a membership vote.
Former Cabinet minister Damian Green at the weekend was rejected as the party's candidate for a newly created seat.
It has driven speculation that MPs who played a part in Mr Johnson's downfall could face the wrath of grassroots activists.
Mr Green, who was effectively deputy prime minister under Theresa May, said he was "disappointed" not to have been selected for the Weald of Kent constituency.
Mr Campbell Bannerman said the MPs who forced a change of leader are the reason the party is lagging in the polls.
“What we're facing are about 60 MPs [who were] determined to bring down Boris and bring down Liz Truss under any circumstances,” he told Times Radio’s Matt Chorley programme.
"And I think it's right in this selection process to hold them to account. Because they've done enormous damage."
Asked if this means as many as 60 Tory MPs could be selected, Mr Campbell Bannerman said: "Well, 60 is a loose list because they've signed letters against Boris and resigned and sought to bring him down and they will be held to account for that.
"And some of those will be deselected I think quite rightly, because of their activities. We've gone from around 2% to 4% behind in the polls to nearly 30% behind, it's complete meltdown."
Mr Johnson was forced out by his MPs last September following months of criticism over Partygate.
Both he and Rishi Sunak received police fines for a lockdown-busting gathering in Downing Street to mark his 56th birthday, while aides held boozy parties including on the night before the funeral of Prince Phillip.
He finally quit as PM after it emerged he had not told the truth about what he knew about sex harassment allegations against Tory MP Chris Pincher when he appointed him as deputy chief whip.
Mr Johnson attempted to make a rapid comeback when Liz Truss announced she was resigning after just seven weeks in Downing Street, but he withdrew from the contest after Mr Sunak won the backing of significantly more Tory MPs.
The former PM still faces a looming Commons privileges investigation into allegations he misled MPs over Partygate. If he is found guilty, he could be suspended and ultimately kicked out of Parliament.
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